Various methods are known for producing containers associable with airless pumps, such as that described in patent application EP2366529 (A1), in the name of the same applicant.
The known methods consist of blow-moulding a preform of polymer material, heated to its softening point, directly in the interior of a hollow body, such as to cause said preform to assume the shape of the hollow body interior. Essentially, this preform is transformed into a deformable bag formed in the hollow body interior.
An airless pump is sealedly associated with the bag after the bag inside the hollow body has been filled with a fluid to be dispensed.
During dispensing by the pump, the bag inside the container gradually deforms as the product is dispensed; in fact, the prerogative of airless pumps is precisely that they do not enable air to enter the bag from the surrounding atmosphere to replace the product dispensed. Hence at each dispensing operation, the bag slightly contracts. In this manner, the product does not enter into contact with air withdrawn from the atmosphere, hence remaining isolated.
In other words, product dispensing causes squeezing of the bag, as the airless pump prevents external air from entering the bag. The result is that the bag inside the hollow body is gradually squeezed onto itself as the product is dispensed.
Current production methods offer considerable advantages in terms of performance and appearance as the bag is formed directly within the external body in which it is to be housed.
However these methods are fairly costly and require process times and optimizations which can be implemented only for high range lines, intended for very costly products.